地应力和储层压力对煤层气地面预抽影响的数值模拟研究  

Numerical Simulation Study on Influence of Geostress and Reservoir Pressure on Ground CBM Pre-extraction

作　　者：江万刚[1,2] JIANG Wangang(State Key Laboratory of the Gas Disaster Detecting,Preventing and Emergency Controlling,Chongqing 400037,China;CCTEG Chongqing Research Institute,Chongqing 400037,China)

机构地区：[1]瓦斯灾害监控与应急技术国家重点实验室 [2]中煤科工集团重庆研究院有限公司

出　　处：《矿业安全与环保》2019年第4期35-39,44,共6页Mining Safety & Environmental Protection

摘　　要：为分析煤层气地面预抽效果影响规律,采用Comsol数值模拟软件,对在不同工况的地应力和储层压力条件下煤层气地面预抽进行数值模拟研究,结果表明:随着煤层中地应力增大,煤层基质孔隙率下降、裂隙趋于闭合,致使煤层渗透率降低,减小了气体在孔隙和裂隙中的渗流速率,最终导致瓦斯产出速率和产气量的下降;储层压力与煤层气产出速率呈正相关关系,储层压力越大,瓦斯产出率越高同时累计产气量也越高;随着瓦斯抽采时间增加,煤层渗透率逐渐增大,且储层压力越大煤层渗透率变化越明显。In order to analyze the influence law of ground pre-extraction effect of CBM,Comsol numerical simulation software was adopted to carry on numerical simulation research on ground pre-extraction of CBM under different geostress and reservoir pressure conditions.The results show that with the increase of geostress in coal seam,the porosity of matrix decreases and cracks tend to close,as a result,the permeability of coal seam decreases,which reduces the percolation rate of gas in pores and fractures,and finally leads to the decline of gas production rate and gas production volume;reservoir pressure is positively correlated with CBM production rate,the higher the reservoir pressure,the higher the gas production rate,and the higher the cumulative gas production;with the increase of gas extraction time,the permeability of coal seam increases gradually,and the change of permeability of coal seam becomes more obvious with the increase of reservoir pressure.

关 键 词：煤层气 地应力 储层压力 地面井 瓦斯抽采 数值模拟 

分 类 号：TD712.6[矿业工程—矿井通风与安全]